Kastelijn, E.A., et al. “YKL-40 and Matrix Metalloproteinases As Potential Biomarkers of Inflammation and Fibrosis in the Development of Bronchiolitis Obliterans Syndrome”. Sarcoidosis, Vasculitis and Diffuse Lung Diseases, vol. 30, no. 1, Apr. 2013, pp. 28-35, https://mattioli1885journals.com/index.php/sarcoidosis/article/view/2765.